Mondays Lab:

1)Truncatable Prime
A number n is called left truncatable prime if n and all numbers obtained by
successively removing its left most digits are prime.(Similarly right truncatable
prime is defined)
Ex 313 is a left truncatable prime>> 313 is prime, 13 is prime, 3 is prime.
   313 is also right truncatable>> 313 is prime, 31 is prime, 3 is prime
Write a C programme which takes a number n as input and then tells whether it is
left truncatable, right truncatable or both



2)Write a program using the function getchar() that inputs a real number and
prints the double of it using putchar(). You are not allowed to use scanf or
printf. You can use ascii code information to convert characters to integers.

Example:
If input is
-23.45
output is
-46.9

3)[ABUNDANT NUMBER]
An abundant number or excessive number is a number n for which Sd_n > 2n. Here Sd_n
is the sum-of-divisors of n: the sum of all positive divisors of n, including n
itself. The value Sd_n-2n is called the abundance of n.
 An equivalent definition is that the proper divisors of the number (the divisors
except the number itself) sum to more than the number.

The first few abundant numbers are:
12, 18, 20, 24, 30, 36, 40, 42, 48, 54, 56, 60, 66, 70, 72, 78, 80, 84, 88, 90, 96,
100, 102

As an example, consider the number 24. Its divisors are 1, 2, 3, 4, 6, 8, 12 and 24,
whose sum is 60. Because 60 is more than 2*24, the number 24 is abundant. Its
abundance is 60 - 2*24 = 12.

Write a C program which takes a number n and prints the abundant numbers less than n.